Our objective is to determine if systemic and pulmonary vascular control are altered during early experimental diabetes. We will study control and diabetic pigs and rats at two to three months after treatment with streptozotocin. Cardiovascular-pulmonary responses to direct, humoral stimulation with angiotensin II, norepinephrine, and prostaglandin F2 alpha and to neural reflex stimulation elicited by bleeding will be examined in intact, anesthetized pigs. Pulmonary vascular reactivity and cardiovascular reflexes to alveolar hypoxia will also be studied. To provide further information of vascular reactivity in control and diabetic animals, studies involving isolated, perfused hind limbs and lungs and isolated systemic and pulmonary vascular strips will be performed. These experiments will indicate whether early diabetes results in abnormal vascular function and at what level of the vascular control system the abnormality occurs.